Director Jon Favreau and the Marvel crew were understandably nervous going in, as "Iron Man 2" had to overcome the hurdle of the high standard set by last year's hit movie.

But during Saturday's presentation, which combined star power, Robert Downey Jr.'s charisma, and masterful showmanship, Marvel showed a fake, subpar sizzle reel before unveiling footage that wowed -- not only meeting the high expectations but surpassing them judging by chatter from the convention floor to Saturday night's parties. It was a textbook example of what a Comic-Con presentation should be.

Managing expectations is one of the trickier tasks studios face in confronting Comic-Con fans. "Avatar," for example, found itself in the crosswinds: James Cameron's 3D movie is not based on a comic or video game that might fuel fan anticipation. It was greeted warmly Thursday but not ecstatically, indicating the movie will have to build awareness in advance of its Dec. 18 release.

"We have to create the equivalent value of an existing brand without there being an existing brand," Cameron told The Hollywood Reporter (read the full Q&A). "We have to make our own brand."

The director said Comic-Con represented only part of the first of three stages of marketing for the movie. Next, the film will take its case to audiences with an unusual 15-minute preview that hits theaters Aug. 21.

The raucous reception for "Iron Man 2" underscored the value of coming in with a branded property, a lesson "New Moon," another sequel with strong pre-awareness, learned earlier during the convention when it garnered favorable responses from fans.

But in a departure from recent years, new properties also caught fire during the weekend.

Most notably, "District 9," a human-vs.-alien action movie based on an original idea that Peter Jackson produced and godfathered, was among the breakouts of the film presentations. Despite no stars, an obscure title and a $30 million budget, the pic, which will be released in August, generated strong buzz -- first among media during a private screening and then among fans at a Jackson-led panel.

That the movie enjoyed such success at Comic-Con underscored another emerging film trend: studios' increased willingness to bring pics that will be released within the next few months, and hesitancy to bring next summer's films.

Outside of "Iron Man 2," all the big film titles will be out in this year, a list that includes "District 9" as well as November-December pics "Sherlock Holmes," "Avatar" and "2012."

Meanwhile, several other movies illustrated a new trend at Comic-Con: Movies without distribution in place using the event to build buzz and gain attention as if it were a bona fide film festival. "Kick-Ass," Matthew Vaughn's adaptation of a Mark Millar comic with Nicolas Cage in the cast, "Solomon Kane," starring James Purefoy, and Joe Dante's 3D horror movie "The Hole" were among the projects hitting the cavernous Hall H in hopes that love from the geek crowd would translate into love from distributors.

Vaughn said it best to the crowd before he screened scenes from his over-the-top actioner Thursday: "If you all give us the thumbs up, we might get distribution. Thumbs down, we're fucked." The hall responded with thumbs held high.

The coming weeks will reveal the fate of these movies.

The Con, which again operated at capacity, grew out of the San Diego Convention Center for the first time. Several panels, notably NBC's "Heroes," took place at the newly opened Bayfront Hilton.

Disney, meanwhile, made a promotional move that portends the future. The studio took the bold step of taking a viral campaign for "Tron: Legacy" into the city's Gaslamp district instead of setting up shop on the convention floor.

The studio, working with 42 Entertainment, re-created a 1980s arcade with actual period games and a new Tron game that revealed a secret passage filled with the new movie's concept art and ultimately led to a Lightcycle -- a special motorcycle seen in the movie -- revolving on a platform.

The setup, named "Flynn's Arcade," drew hundreds of fans who lined up for more than an hour and showed that awareness could be launched from beyond the confines of the cramped convention center, something Hollywood and Comic-Con need to consider if the conclave is to continue growing.

Convention organizers were disappointed to see Disney move out.

"One of the things that we lose that studios bring is revenue that helps put on the convention," Comic Con director of marketing David Glanzer said. "But we did see an increase in television this year with panels and huge sponsorship opportunities, and that helps with many things including rental space and ancillary costs."

He added that the Bayfront Hilton experiment worked well, predicting, "We'll hopefully use that or a similar space in the future."